Heretofore, determination of the color of liquids has consisted of placing a specimen into a container which is attached to an optical system in an instrument such as a spectrometer or other color determining instrument, whereby only the color of the transmitted light is measured by the particular method of color determination.
However, in actual practice, the colors in both the transmitted light and reflected light for a liquid stimulate the visual nerve. Therefore, it is necessary to determine the color of both types of light simultaneously to evaluate the color of the liquid.
There has been, thus far, no instrument that can determine the color of the aforesaid two types of light. Although a turbidity-measuring instrument has heretofore been available, it is designed to measure the degree of light scattering caused by the particles in the liquid, and it has not been helpful in the evaluation of color.